AC Not Cooling

When the summer heat and humidity hit Greater Montreal, an ac not cooling is a major frustration. You expect your home to be a comfortable retreat. Instead, you are left sweating indoors while your energy bills climb. If your air conditioning system is blowing warm air or running constantly without lowering the temperature, you need fast and reliable answers.

Service Servotech is your local expert for home appliance and HVAC repair across Montreal, Laval, the West Island, the South Shore, and the North Shore. We offer fixed rates and are available seven days a week, including evenings. Our certified technicians have the experience to diagnose your system quickly, fix the problem safely, and restore your home comfort with guaranteed workmanship.

If you are dealing with a hot house right now, call us to book a repair. Otherwise, read on to discover the most common reasons your system is failing and what you can do about it.

Why Is My AC Not Cooling the House?

It is incredibly frustrating when you hear your system turn on, but the indoor temperature stays exactly the same. When your ac at home is not cooling, the system is usually failing at one of two jobs: it is either unable to absorb heat from your indoor air, or it is unable to release that heat outside.

A central air conditioner relies on a careful balance of airflow, refrigerant pressure, and electrical power. If just one component fails, the entire cooling cycle stops. Identifying the root cause early saves you from expensive compressor damage and restores your comfort faster.

AC Is Running But Not Cooling: First Steps to Check

Before you call a technician, you can perform a few safe checks. Sometimes, the solution is simpler than you expect. If your ac is running but not cooling, look at these basic areas first.

Quick Diagnosis Checklist

• Check the vents: Ensure all room vents are open and unblocked by furniture or rugs.
• Check the electrical panel: Look for a tripped breaker. Canadian electrical standards require dedicated 240V circuits for central cooling systems. A power surge can easily trip this breaker.
• Check the outdoor unit: Ensure the fan is spinning and the unit is clear of debris.

If these basic elements look normal, the issue requires a deeper inspection.

Thermostat Issues Keeping Your AC Working But Not Cooling

Your thermostat is the brain of your climate control system. If your ac working but not cooling is the main symptom, the thermostat might be sending the wrong signals.

First, verify that the fan setting is on “Auto” instead of “On”. When set to “On”, the fan blows air constantly, even when the cooling cycle is resting. This causes the system to circulate warm air through your vents. Next, replace the thermostat batteries. A weak battery can cause the unit to lose its connection to the main system. If the settings are correct and the batteries are fresh, the internal wiring may be faulty and require professional repair.

Clogged Air Filters Restricting Cold Airflow

A dirty air filter is the most frequent reason homeowners ask why is my ac not cooling. Your system needs a steady flow of warm air from your house to pass over the cold indoor coils.

When a filter is clogged with pet hair, dust, or pollen, airflow stops. The system works twice as hard to pull air through the dirt. This strains the blower motor and often causes the indoor coils to freeze solid. Check your filter every month. If you hold it up to a light and cannot see through it, replace it immediately.

Blocked Outdoor Condenser Units in Your Central AC

The outdoor unit of your air conditioner is responsible for releasing the heat absorbed from your home. In Quebec, outdoor units face harsh conditions. Melting winter snow leaves behind mud, while spring brings sticky tree sap and cottonwood fluff.

If the metal fins on the outside of your condenser are blocked by dirt, leaves, or overgrown bushes, the heat stays trapped inside the system. Your central ac unit not cooling properly is often a direct result of this blockage. Keep a clearance of at least two feet around the entire outdoor unit. You can gently wash the outside fins with a garden hose, but never use a pressure washer, as this will crush the delicate metal.

Frozen Evaporator Coils and Refrigerant Leaks

If you notice ice forming on your indoor unit or on the copper pipes outside, you have a frozen evaporator coil. This happens when there is a severe lack of airflow or a refrigerant leak.

Refrigerant is the chemical that actually cools the air. It operates in a closed loop and is never “used up”. If the level is low, there is a leak. When refrigerant drops, the pressure changes, causing the coils to drop below freezing. Moisture in the air then freezes directly onto the coils. Handling refrigerant requires strict adherence to Canadian environmental regulations. Only a licensed professional can safely locate the leak, repair the copper lines, and recharge the system.

Why Your Central AC Not Cooling Upstairs Is a Ductwork Issue

Many homeowners in two-story homes notice their central ac not cooling upstairs, even when the main floor feels comfortable. Heat naturally rises, making the second floor harder to cool. However, severe temperature differences usually point to ductwork problems.

Leaks, cracks, or disconnected ducts in your attic or walls allow cold air to escape before it reaches your bedroom vents. Additionally, an undersized air conditioner will lack the power needed to push heavy, cold air up to the second level. A professional inspection will determine if your ducts need sealing or if your system sizing is incorrect.

Condo AC Not Cooling: Special Considerations for Apartments

Living in a high-rise presents unique challenges. If you have a condo ac not cooling, the troubleshooting process is slightly different. Many Montreal condominiums use shared water-loop systems or have strict strata rules regarding balcony units.

If your condo uses a localized heat pump or a fan coil unit, the building management may control the main water temperature. Always check if your neighbors are experiencing similar issues before booking a repair. If the problem is isolated to your unit, the internal fan motor, the local thermostat, or a blocked drain line is likely to blame.

When to Turn Off Your AC If It Is Not Cooling Properly

Knowing when to stop using your system is critical. If your ac is on but not cooling, forcing it to run will eventually destroy the compressor. The compressor is the most expensive part of your entire system.

Turn off your system immediately if you notice:

• Ice building up on the indoor or outdoor copper pipes.
• A loud hissing or bubbling noise indicating a chemical leak.
• A burning electrical smell coming from the vents.
• The system running for hours without dropping the room temperature by a single degree.

Shutting the power off protects the equipment and gives frozen coils time to thaw before the technician arrives.

How Regular Maintenance Prevents Your AC from Losing its Cool

The best way to stop a breakdown is to prevent it before the hot weather arrives. Quebec summers are hot and humid, placing massive strain on cooling equipment. Annual maintenance keeps your system running efficiently and extends its lifespan.

During a routine service visit, a technician cleans the internal components, tests the electrical connections, and verifies the chemical pressures. This proactive approach catches small wear-and-tear issues before they turn into complete system failures on a 30-degree day.

DIY vs Professional Repair

Task	Homeowner Action	When to Call Service Servotech
Air Filter	Replace every 30 to 90 days.	If the system still blows warm air after a filter change.
Thermostat	Change batteries and set to “Auto”.	If the screen is blank or the wiring is damaged.
Outdoor Unit	Clear leaves and gently hose off dirt.	If the outdoor fan motor is making grinding noises or fails to spin.
Refrigerant	Look for ice on the pipes.	Always call a pro. Handling refrigerant requires strict Canadian licensing.

Why Choose Service Servotech for Your Cooling Repairs

When your home is uncomfortably hot, you need a team you can trust. Service Servotech is dedicated to providing fast, reliable, and transparent repair services to Canadian homeowners.

• Local Expertise: We proudly serve Greater Montreal, Laval, the West Island, the South Shore, and the North Shore.
• Available 7 Days a Week: Cooling emergencies do not wait for Monday morning. We offer evening and weekend appointments.
• Fixed Rates: You will never be surprised by hidden fees. We provide clear, transparent pricing before any work begins.
• Licensed and Insured: Our technicians are fully certified to work with high-voltage systems and chemical refrigerants according to all local safety standards.
• Guaranteed Workmanship: We back our repairs with extended warranties on both parts and labour.

Frequently Asked Questions

Why is my ac running but not cooling the house? The most common reasons are a dirty air filter blocking airflow, a blocked outdoor condenser unit, or a low refrigerant level caused by a leak. Check your filter and thermostat first, then call a professional if the issue persists.

Why my ac is not cooling but the fan is on? If the fan is running but the air is warm, your thermostat might be set to “On” instead of “Auto”. It could also mean the outdoor compressor has failed to start due to a bad capacitor or a tripped breaker.

Can I add refrigerant to my air conditioner myself? No. In Canada, only certified and licensed HVAC technicians are legally permitted to handle, recover, and recharge air conditioning refrigerants due to strict environmental and safety regulations.

How do I fix an ac not cooling upstairs? First, ensure all vents on the upper floor are fully open. You can also partially close a few vents on the main floor to force more cold air upward. If this fails, you likely need a professional to inspect your ductwork for leaks or evaluate your system capacity.

What should I do if my ac is on but not cooling and I see ice? Turn the system off immediately. Ice indicates a frozen evaporator coil, usually caused by restricted airflow or a chemical leak. Running the system while frozen will severely damage the compressor. Call Service Servotech to diagnose the root cause safely.